Novel process for generating hemp oil with a high cannabidiol (cbd) content

ABSTRACT

A method for producing hemp oil, comprising decarboxylation of CBDA in hemp oil; short-path evaporation of CBD from the decarboxylated hemp oil to produce CBD oil; selective THC to CBN conversion performed on the decarboxylated hemp oil.

BACKGROUND

1. Technical Field

The embodiments described herein are related to generating hemp oil, andmore particularly to an improved process that generates hemp oil with ahigh CBD content.

2. Related Art

Cannabinoids are a class of diverse chemical compounds that act oncannabinoid receptors on cells that modulate physiological responses inthe brain, peripheral nervous and immune systems. The nativeendocannabinoid ligands (produced naturally in the body by humans andanimals), the phytocannabinoids (found in cannabis and some otherplants), and synthetic cannabinoids (manufactured chemically) bind toreceptors throughout the body and control downstream signaltransduction. One example of a cannabinoid is Cannabidiol (CBD), whichis a major substituent in hemp and hemp extracts. The chemical compoundfor CBD is illustrated in FIG. 5. Some researchers believe that CBDshows promise of potential clinical applications in a variety of medicalconditions. It may have multiple potential applications such as for thetreatment of epilepsy and other motor disorders, inflammation, mood andanxiety disorders, sleep dysfunction and eating disorders. CBD is alsoconsidered a promising antineoplastic agent on the basis of its in vitroand in vivo activity against tumor cells.

The endocannabinoid system (ECS) regulates many physiological processesinvolved in relaxation, eating, sleeping, certain inflammatory responsesand even cognitive function. There are two types of cannabinoidreceptors found throughout the body (CB1 and CB2), but they are mostabundant in the brain and immune system respectively. In fact, the CB1receptor is the most densely populated G-coupled protein receptor in thehuman brain. New evidence indicates that a cannabinoid-like ligands acton wide variety of biological targets, such as the transient receptorpotential cation channel, nuclear receptors and other orphaned G-coupledprotein receptors (i.e., TRPV1, PPAR, GPR18 and GPR55), and represents afascinating area to develop new therapeutic targets.

CB1 receptors are found primarily in the brain, more specifically in thebasal ganglia and in the limbic system, including the hippocampus. Theyare also found in the cerebellum and in both male and femalereproductive systems. CB1 receptors are absent in the medulla oblongata,the part of the brain stem responsible for respiratory andcardiovascular functions. Thus, there is not the risk of respiratory orcardiovascular failure that can be produced by some drugs, such asopioids. CB1 receptors appear to be responsible for the euphoric andanticonvulsive effects of cannabis.

CB2 receptors are predominantly found in the immune system orimmune-derived cells with the greatest density in the spleen. Whilefound only in the peripheral nervous system, a report does indicate thatCB2 is expressed by a subpopulation of microglia in the humancerebellum. CB2 receptors appear to be responsible for theanti-inflammatory and possibly other therapeutic effects ofcannabinoids. CBD binds only weakly to both the CB1 and CB2 receptorsites and its health benefits cannot be explained with traditionalcannabinoid receptor binding. It is unclear how CBD functions and itsmechanism of action is a current topic of investigation.

In order to harness the benefits of CBD, processes have been developedto extract the CBD in hemp oil made from the hemp plant. The percentageof CBD in the hemp oil is therefore an important metric.

SUMMARY

The embodiments described herein illustrate a process for producing hempoil with a high CBD content.

A method for producing hemp oil, comprising decarboxylation of CBDA inhemp oil; short-path evaporation of CBD from the decarboxylated hemp oilto produce CBD oil; selective THC to CBN conversion performed on thedecarboxylated hemp oil.

These and other features, aspects, and embodiments are described belowin the section entitled “Detailed Description.”

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and embodiments are described in conjunction with theattached drawings, in which:

FIG. 1 illustrates the selective thermal degradation (80° C.) of THCcontent over time in the hemp oil;

FIG. 2 illustrates the percentage of the original mass overtime duringthermal degradation;

FIG. 3 is an illustration of the 2 stage short path distillation plantthat can be used in the process of FIG. 4;

FIG. 4 is a flow chart illustrating and example process for producinghemp oil with a high CBD content in accordance with one embodiment;

FIG. 5 is a diagram illustrating a CBD compound;

FIG. 6 is a diagram illustrating a CBN compound; and

FIG. 7 is a diagram illustrating a THC compound.

DETAILED DESCRIPTION

Various steps for producing hemp oil are described below. It will beunderstood that certain steps described can be optional and that theorder of the steps may vary. FIG. 4 is a flow chart illustrating anexample process for producing hemp oil with a high CBD content inaccordance with one example embodiment.

The process can start, in step 402, with Decarboxylation ofcannabidiolic acid (CBDA) in Hemp Oil, which can start with virgin CO2extracted hemp oil that has been extracted from the whole plant. Thevirgin CO2 extracted hemp oil generally has large amounts ofcannabidiolic acid (CBDA), the precursor to cannabidiol (CBD). Thevirgin hemp oil can be decarboxylated by heating to about 150° C., e.g.,to a temperature in the range of 140° C. to 160° C. between 10-18 hours,to convert the CBDA to CBD. This procedure can be carried out in a feedtank equipped with a heat transfer oil filled jacket and a venting portto prevent pressure from building up in the vessel.

Upon reaching the decarboxylation temperature, carbon dioxide begins tovigorously boil out of the solution. The bubbling may provide sufficientmixing and will typically subside as the process nears completion;however, if required, additional mixing can be performed using anagitator, in optional step 404. The temperature can then be lowered tobetween 75-90° C. and the melted contents can then be poured into foodgrade vessels that can then be stored in a cool dry environment.

At this point, in step 406, cannabinoid content should be measured toensure full decarboxylation has taken place. If not, then the processshould be repeated until full decarboxylation has taken place (<0.1%CBDA).

Next, in step 408, short-path evaporation of CBD from decarboxylatedhemp oil can be performed. In this step, CBD can be isolated from thecrude decarboxylated CO2 extract using two tandem short-path evaporationsteps. Generally, up to 60% (w/w) CBD is obtained using the optimizedconditions depending on the input feed material CBD concentration.30-200 kg of decarboxylated hemp oil can be placed in the feed tank ofa, e.g., model KD10 (ChemTech Services) short-path evaporator. The feedtank heat transfer oil bath can be set at 90-150° C. and the solidallowed to fully melt. A vacuum range of 0.5-0.08 torr for evaporator #1should then be maintained with, e.g., two vacuum pumps (D65B andWAU251). Evaporator #2 was equipped with an Edwards EO50/60 DiffusionPump capable of achieving an ultimate vacuum of approximately 0.005torr. The wiper baskets can be set to, e.g., rotate at about 70% of themaximum speed. Evaporator #1 can be set to a range of 250-270° C.,depending on the vacuum at system equilibrium and fed at a rate of 2-3.5Hz from the feed tank pump. Evaporator #2 temperatures of 160-175° C.are generally found to be optimal. The distillate from evaporator #1 istransferred directly to evaporator #2 at the speed at which it isrecovered.

The first step in this sub-process (evaporator #1) is intended to removeas much light boiling volatile components as possible from theCBD-containing feedstock. The second step, of this sub-process,in-series evaporator #2 is used to refine the CBD from the high boilingpoint components in order to achieve maximum purity. FIG. 3 is anillustration of the 2 stage short path distillation plant.

The distillate can then be collected in food grade vessels and stored ina cool dry environment, in step 410. Cannabinoid content in both thewaste residue and distillate should be measured and mass balancedetermined.

The next step (412) can be selective THC to CBN conversion. The purposeof this sub-procedure is to convert residual THC content to cannabinol(CBN) without causing a significant reduction in CBD levels. FIGS. 5 and6 illustrate example CBN and THC compounds respectively.

The CBD oil purified using short-path evaporation can then, in step 414,be loaded into, e.g., Pyrex baking dish to maximize surface area toatmospheric oxygen and heated from 80-100° C. for a few days to a fewweeks. Cannabinoid content is carefully monitored periodically over theconversion period. The hot oil can then be collected in food gradevessels and stored in a cool dry environment.

Using the process described herein, it has been demonstrated that up to60% CBD/<1% THC can be obtained starting from material with variablecannabinoid content. FIG. 1 illustrates the selective thermaldegradation (80° C.) of CBD and THC percent content over time in thehemp oil. The y-axes represent the THC and CBD percentages, and thex-axis shows days.

FIG. 2 illustrates the percentage of the original mass overtime duringthermal degradation. The y-axis represents the percent of eachcannabinoid relative to the original percent prior to heating. Inaddition to minimizing THC content, the procedure described hereindecreases the difficulty of isolating pure CBD in future purificationsteps. Table 1 contains the raw data used to construct the plot.

TABLE 1 % Original % Original Day CBD % Mass CBD THC % Mass THC 1 47.5100 1.9 100 17 47.05 99 1.57 83 27 45.72 96 1.12 59 35 44.39 93 0.94 4937 41.01 86 0.27 14

Next, a winterization procedure can be performed in step 416. Thewinterization procedure is designed to remove plant wax impurities fromthe product. In this procedure the hemp oil is diluted to about 10%(w/w) in isopropanol, placed in a freezer at about −20° C. overnight,and vacuum filtered through a bed of sand at about −20° C. A white solidcan then be collected and washed 2× with cold isopropanol. The filtratecan be combined and the solvent stripped under heat in vacuo to producea red gel.

The red gel can then be brought to about 80° C., in step 418, collectedin high-density polypropylene vessels, and stored in a cool dryenvironment. Cannabinoid content should be measured to determine thepurity of the isolate.

Next a silica plug procedure can be performed in step 420. Thisprocedure is performed to remove highly polar impurities that stick tothe baseline of normal phase silica gel, which increases purity andreduces overall loading mass in the next process chromatography step. Inaddition, the silica plug extends the life of the silica gel used duringflash chromatography purification. A large glass fritted filter funnelcan be charged with silica gel slurry made from, e.g., 95% hexane and 5%ethyl acetate and situated on an Erlenmeyer flask with a sidearm. Thewinterized CBD-rich oil can then be dissolved in a minimum amount ofhexane and loaded onto the top of the column containing a 5:1 silicagel:CBD oil ratio. The product CBD was eluted with a 95% hexane to 5%ethyl acetate solution and collected in fractions. The fractionscontaining CBD can be combined and the solvent stripped using heat andvacuum to afford a red oil. The red oil can be brought to 80° C. andcollected in high-density polypropylene vessels and stored in a cool dryenvironment. Cannabinoid content should be measured to determine thepurity of the isolate.

Next, in step 422, flash chromatography purification of CBD from hempoil can be performed. The red oil from the silica plug can be diluted ina minimum amount of hexane and loaded on a, e.g., Biotage KP-Sil 1500 gcolumn equilibrated with 93% hexane 7% ethyl acetate with an automatedperistaltic pump. This procedure can be carried out on a Biotage IsoleraLS using a dual wavelength UV detector (215, 235 nm). An isocraticgradient consisting of about 93% hexane to about 7% ethyl acetate can bemaintained throughout the run. The CBD fraction can then be isolated andthe solvent removed in vacuo to yield a golden oil. Residual solventcontamination can be removed by placing the oil under high vacuum (0.005torr) at about 80° C. for about 72 hours. The remaining golden oil canthen be transferred to glass vials and stored at about 4° C. Cannabinoidcontent should be measured to determine the purity of the purifiedfractions.

While certain embodiments have been described above, it will beunderstood that the embodiments described are by way of example only.Accordingly, the systems and methods described herein should not belimited based on the described embodiments. Rather, the systems andmethods described herein should only be limited in light of the claimsthat follow when taken in conjunction with the above description andaccompanying drawings.

What is claimed:
 1. A method for producing hemp oil, comprising:decarboxylation of CBDA in hemp oil; short-path evaporation of CBD fromthe decarboxylated hemp oil to produce CBD oil; and a selective THC toCBN conversion performed on the decarboxylated hemp oil.
 2. The methodof claim 1, wherein decarboxylation of CBDA in hemp oil comprises:starting with virgin CO2 extracted hemp oil that has been extracted fromthe whole plant; decarboxylating the virgin CO2 extracted hemp oil byheating to 140-150° C. for 10-18 hours to convert the CBDA to CBD. 3.The method of claim 5, wherein upon reaching about 150° C., mixing theresultant solution and then lowering the temperature to about 80° C. 4.The method of claim 1, wherein the short-path evaporation of CBD fromthe decarboxylated hemp oil to produce CBD oil comprises isolating theCBD from a crude decarboxylated CO2 extract generated by decarboxylationof CBDA in hemp oil using two sequential short-path evaporation steps,and wherein the first step comprises: placing decarboxylated hemp oil ina feed tank of a first short-path evaporator; setting the feed tankheater to about 140° C. and allowing the decarboxylated hemp oil tofully melt; maintaining a vacuum of at least 0.5 torr to 0.08 torr withprimary vacuum pump.
 5. The method of claim 7, wherein the evaporator #1is set to 250-275° C. with a feed rate of 2-3.5 Hz from a feed tankpump.
 6. The method of claim 7, wherein the second step comprises usinga second evaporator to refine the CBD to maximum purity.
 7. The methodof claim 9, wherein the second evaporator is set to 160-170° C. and isequipped with an additional diffusion pump capable of achieving anultimate vacuum of 0.5-0.005 torr. Evaporator #2 is fed at a rateconsistent with the output of the residue from evaporator #1.